Answer
given,
Weight of the child = 110 N
length of the swing,L = 2 m
now, calculating the potential energy when the string is horizontal
Potential energy = m g h
now, h = L (1 - cos θ) where θ is the angle made by the string with the vertical.
PE = m g L (1 - cos θ)
when rope is horizontal θ = 90°
PE = 110 x 2 (1 - cos 90°)
PE = 220 J
now, calculating potential energy when string made 25° with horizontal
PE = m g L (1 - cos θ)
when rope is horizontal θ = 25°
PE = 110 x 2 (1 - cos 25°)
PE = 20.61 J
Answer:
13 km/h for 65 km
9 km/h for the next 27 km
Explanation:
Velocity of canoe =x km/h for 65 km
Velocity of canoe =x-4 km/h for 27 km after covering 65 km
Total time taken = 9 hours
So,
Solving this quadratic equation we get,
Speed cannot be 2.5 as the speed will become negative for the 27 km stretch.
So, velocity of canoe is <u>13 km/h</u> for 65 km and <u>9 km/h</u> for the next 27 km
Conservation means to improve something to prevent loss or decay
That's why energy can't be created or destroyed
The Earth's spin in its axis each 24 hours
